The overall aim is to provide information concerning the influence of nutritional factors in normal development, and the role of suboptimal nutrition in the birth of offspring with abnormalities deleterious to postnatal life and development. Elucidation of the role of zinc in mammalian development, especially the effects of mild or marginal deficiency during gestation and the mechanisms by which they are produced are more specific aims, as is also elucidation of the mechanisms whereby maternal magnesium deficiency results in severe fetal anemia.